1. Field of the Invention
The present invention relates generally to rotary shaft couplings, particularly to rotary shaft couplings transmitting torque via radially directed pins, and most specifically to rotary shaft couplings transmitting torque via radially directed pins that are further bearing mounted.
2. Discussion of the Prior Art
Use of two perpendicular torque transmitting radially directed pins, or more accurately one pin and two opposed pin portions, or four pin portions, contacting a central member with intersecting axes is well known in what is commonly called a Cardan joint. Bearing mounted pins in a Cardan joint also known include: GB 0 284 089, GB 0 680 213, FR 1 186 634, and GB 2 129 524; while CH 0 364 666 discloses bearing mounting of the ends of a cruciform member with intersecting radial axes, similar to a Cardan joint, within the apposed ends of two radially perpendicular yokes.
Use of two perpendicular torque transmitting radially directed solid pins axially spaced apart from each other is less well known, bearing mounted or not. The only two known were disclosed by SU 0 317 842 and FR 2 515 129. Neither use bearings to mount the radial torque pins although the first uses bearings to mount each opposed hub of the coupling. Both provide for accommodation of angular misalignment: with axial slots for the ends of the pins in the former and a necked plastic bushing between the pins and the inwardly convex interior surface of the aperture through the coupling member for each pin in the second.
3. Statement of Need
While bearing mounting of intersecting axes radial torque pins in Cardan type rotary shaft couplings are known and axially spaced dual radial torque pins are known, and both are accommodative of angular misalignment between coupled shafts, no rotary shaft coupling utilizing radial torque pins capable of radial displacement, necessary for accommodation of parallel misalignment between coupled shafts, is known and a need for the same hence discerned.